Electrical connection circuit breaker



May 12, 1942. A. KEEFE 2,282,967

ELECTRICAL CONNECTION CIRCUIT BREAKER Filed Feb. 11, 1958 7' 54 l/IA 5056 F INVENTOR Arthur Keefe BY F1 7 J 67 ATT'ORNEY a Patented May 12,1942 ELECTRICAL CONNECTION CIRCUIT.

BREAKER Arthur Keefe Akron, Ohio Application February 11, 1938, SerialNo. 190,088 Claims. (01. 200-1155) This invention relates to circuitbreakers and more particularly to means in the form of electricalconnecting devices for replaceably interrupting an electrical circuit inthe event of a current overload. v

An object of the present invention' is to provide a circuit breaker inthe form of electrical connections that are of simple and inexpensiveconstruction and assembly, safe and dependable in operation, and of longlife and durability.

silient rubber plug receptacle I that is shown is advantageous in thatit may be simply and firmly installed in its aperture by merely pressingit thereinto.

The plug receptacle may or may not, as desired, be provided with thefrustro-conical lead edge 6 that facilitates the advance of the plugreceptacle past irregularities in the face of the aperture in which itis installed. The resilient,

A further object is to provide a circuit breaker Another object is toprovide a circuit breaker that comprises self-acting release membersthat are simply and easily re-engaged.

With the above and other objects in view that will be apparent to thosefamiliar with the art to which the present invention pertains from thefollowing description, suitable illustrative embodiments of theinvention are disclosed in the accompanying drawing, wherein:

Fig. 1 is an elevational section with parts broken away, of the circuitbreaker applied to an electrical connection combination of a plug and aplug receptacle that is mounted in a wall;

Fig. 2 i an elevation of the plug that is shown in Fig. 1;

Fig. 3 is an elevation that is partly broken away, of the plugreceptacle that is shown in Fig. 1;

Fig. 4 is an elevational end view taken from the line 4-4 of Fig. 3;

Fig. 5 is a transverse section taken along the line 55 of Fig. 4;

Fig, 6 is an elevation of a modified plug receptacle in section and aplug, partly broken away; and

Fig. 7 is an elevational section of a modified plug that embodies theinvention.

The circuit breaker may be housed in any suitable fittings that conformto its functional re-.

, insulating material, such as conventional polymerized resins,porcelain, rubber, or the like, and of any suitable form orconfiguration. The recircumferentially extending retaining flanges 1that are shown are substantially frustro-conical in form sovthat theypresent an inclined surface to the face of the receptacle receivingaperture as the plug receptacle is advanced into its aperture, and ayielding, sharp edge in engagement withthe face of its receivingaperture to resist its being easily dislodged from its installedposition. The retaining flanges I yielding'ly provide a plurality ofcircumferential zones of maximum contact pressure on the face of theaperture in which the receptacle is installed and thereby improve thegrip of the periphery of the plug receptacle on the aperture face.

In many forms of mounting the face of the receptacle receiving aperturemay be sufiiciently rough so that a considerable variety of surfaceconfiguration may be substituted satisfactorily for the particularillustrative form that is shown here. The flanges or surfaceconfiguration may be omitted entirely, if desired, and the retention ofthe plug receptacle be accomplished by the resilience of its bodyportion.

The plug receptacle face flange 8, that seats in the board groove 9, ian optional structure and serves to countersink the plug receptacle inthe board 3 in conventional manner and also controls the degree ofinsertion of the plug receptacle in its aperture.

The body of the plug receptacle I is apertured for the accommodation ofthose parts of the circuit breaker that are housed therein. Theinsulating washer groove III in the inner surface of the plugreceptacle" I, releasably receives the peripheral edge or and providessupport for the insulating, parts supporting heavy washer II, The

copper II that are shown, or other similarly functioning strips ofconventional material. The

. iron and copper strips are welded together adjacent their free ends.The thermally sensitive with platinum, silver or the like, inconventional manner for make and break contacts.

The pointed end of the plug contact tip I3 is advantageous in that inits engagement with the oppositely inclined free tips of the bi-metallicstrips during the engagement of the plug with the plug receptacle itcenters the plug contactand directs the arrow-shaped plug contact tip l9between the free ends of the U-shaped bi-metallic strip until theshoulders I! of the strip engage the plug contact tip l9'back of thebarbs thereof to provide for the normal retention of the engagement andfor the conducting of current of normal magnitude therebetween. In theevent of a temperature increase, as caused by a short circuit thru thethermally responsive strip,

the strip shoulders I1 move away from each' other sufliciently torelease the plug contact tip I9 from therebetween.

The headed screw I6 is disposed within the screw tube 20, extends thruthe parts supporting washer I and is threaded along its end to receivethe nut 2|. The pair of metal washers 22 are disposed on either side ofthe line wire 23 and are interposed between the nut 2| and theinsulating, parts supporting washer The nut 2| on the screw l6 tightlysecures the bi-metallic spring contact between the head of the screw l6and the end of the screw tube 20. The end of the screw tube 20 that isremote from the bimetallic spring contact is supported by the insulatingwasher II.

This union secures the line wire 23 in close electrical connection thruthe screw IS with the plug receptacle contact bi-metallic strip. Themetal washers 22 assist in the perfection of this electrical contact inconventional manner and also serve to distribute the compression forcebetween the screw I6 and the nut 2| over an adequate area of the washerII to prevent substantial injury to the washer Means for making itpossible to prevent the rotation of the screw IS with respect to the nut2| is provided, as by having the screw head slotted at 24 for thereception of a screw driver blade or the like, or in other suitableconventional manner.

Suitable resilient means is provided for opposing the retention of theplug contacts by the plug receptacle contacts, as by the compressionspring 25. The spring 25 is shown to be disposed within the springsleeve 26 that is supported laterally by contact with portions of theresilient plug receptacle and that is disposed substantially centrallythereof. The inner end of the spring sleeve 26 rests against the partssupporting washer The magnitude of the force that opposes the retentionof the plug contacts by the receptacle contacts is preferablyadjustable. In the construction shown, a turn of one end of thecompression spring. 25 is disposed in the circumferential slot 21 in thehead of the spring carrying screw 28. The screw 28 makes adjustablethreaded engagement with the parts supporting washer II and its screwdriver blade receiving The nuts 36 also slot 23 permits the rotation ofthe screw so that the spring 25 may be caused to advance toward or bewithdrawn from the parts supporting washer II and the degree ofits'pressure on the plug 2 be adjusted to a desired value.

The plug 2 is provided with suitable means for engaging the free end ofthe spring 25, as by the plug screw 3|! that is disposed substantiallycentrally of the plug 2 and that is guided and centered in itsengagement with the end of the spring 25 by the sleeve 26 that ispreferably of insulating material. The plug screw 30 is firmly mountedin the plug 2 in any suitable manner, as by being threaded atits innerend into the plug outer insulating split washer 3|, the spacer 32, andthe plug parts mounting inner insu1at ing washer 33. Provision forcausing the rotation of the plug screw 30 is provided, as by the screwdriver blade receiving slot 34 in its head portion, or the like.

The peripheral edge of the plug outer washer 3| is removably seated inthe circumferential slot 35 that extends circumferentially of the innerface of the plug 2. The plug inner washer 33 is maintained firmly inposition, as by being of proper diametrical proportion to seat snuglywithin the plug that may be grooved for its reception or not as desired.The washer 33 is preferably maintained in diametrical compression by thecontraction of the resilient body portion of the plug 2. Y The spacer 32is held firmly and securely in position between the outer washer 3| andthe inner washer 33 in a convenient manner, as by being provided withrough and irregular surfaces, or the like.

The plug contacts |8 are also firmly supported in the plug 2 in anysuitable manner, as by extending back thru the plug washers 3| and 33and terminating in a threaded portion on which the nuts. 36 areremovably mounted. The washer 3| is a split washer preferably, forpurposes of ease of "assembly, as is shown in unsectioned elevation inFig. 1 and in dotted section in Fig. 5. secure the appliance cord wires31 in electrical contact with the plug contacts l8 by compressing thewires 31 between the small metal washers 38 and the larger washers 39. Afirm mounting is provided for the plug contacts l8, as by having theirlaterally extending legs 30 compressed between the outer washer 3| andthe inner washer 33. The legs 40 may; if desired, terminate in theaxially extending prongs or spurs 4| that are embedded in the innerwasher 33 and that further improve the stability of the plug contacts inthe plug 2. The washer 3| may be omitted where the washer 33 is seatedin a groove, as is the washer 3|, or otherwise firmly anchored in theplug 2.

In operation the electrical connection combination transmits electricalcurrent of normal magnitude from the line wires 23 thru the thermallyreactive contacts in the plug receptacle and thru the plug contacts l3to the appliance cord wires 31.

In the event of a current overload being imposed on this connectioncombination, however, the heat generated in the thermally reactivestrips by the flow of excess current causes the moving apart of theopposed shoulders I! of the thermally reactive plug receptacle contactsand the release of the arrow-shaped head of the plug contacts Hi, Theadjusted force that is exerted by the compression spring 25 against thehead of the plug screw 30 then kicks the plug 2 away from the plugreceptacle I and the circuit between the plug and its receptacle isbroken. The circuit is resumed on the reinsertion of the plug contactsinto the plug receptacle.

The plug receptacle 42 that is shown inFig. 6, preferably, for ease ofassembly, has the separate base 43 that is secured to the receptacle bythe center contact screw 44 that threads into the core of thereceptacle. The center contact 44 is connected for electricaltransmission to suitable concealed thermally reactive contacts, such asthe bi-metallic strip contacts 45, and thru suitable connecting means,such as the strap 46 and the bolt 41 that secures the strip contacts 45to the receptacle base 43.

The outer contact threaded screw base 48 of the plug receptacle orscrewbase plug, provides contact with the concealed thermally reactiveor bi-metallic strip contacts 49 that are secured within the receptacleby the screw 50 that threads into the base 43. Suitable means, such asthe prongs and 52 on the thermally reactive plug receptacle contactsthat seat in the aperture 53 and 54, respectfully, of the exposedcontacts 55 and 56 of the plug 51, are provided to engage the exposedplug contacts and to retain them. in the plug receptacle against thepressure of the spring 58 that yieldingly resists the engagement. Theouter end of the spring 58 is covered by the cup 59 to provide asuitable cover therefor and to improve the external, appearance of theplug receptacle. The cup 59 is preferably of insulating material.

In operation the thermally reactive plug receptacle contact prongs 5|and 52 remainseated in the apertures of the exposed plug contacts andmaintain the electrical engagement between the plug and the plugreceptacle while normal current loads are being conducted therebetween.When an overload of current is imposed on the connection, however, thespaced ends of the thermally reactive strips separate from each othersufliciently to permit the withdrawal of the prongs 5| and 52 from theapertures in the exposed plug contacts and the pressure of the spring 58kicks the plug away from the plug receptacle thereby breaking theelectrical connection. The re-insertion of the plug exposed contacts inthe plug receptacle re-establishes the electrical connection.

An electrical connector circuit breaker in the form of a push in plug isshown in Fig. '7 of the accompanying drawing. In this construction thethermally reactive releasable connector is disposed in any suitablehousing, such as the plug shell 60, on the end of which the removableplug cap 5| threads. A suitable mounting is provided within the housingfor the rigid operative parts of the connector, such as the partssupporting washer 62 that is secured to a portion of the plug shell 50by the central screw 63. The screw 63 also supports the compressionspring 64, as by having a turn of the spring interposed between the headof the screw and the metal washer 65.

The radially outer screws 66 secure the line wires 31 and the thermallyreactive concealed contact strips 61 to the washer 62.. The prongs 66 onthe thermally reactive contacts removably seat in suitable apertures inthe inner end of the movable exposed contacts 69, that are carried on asuitable mounting, such as on the split washer 10. The parts of thesplit washer are disposed on opposite sides of the shoulders H on themovable contacts 69 and are secured together by suitable-means, such asby the screw 12, that may,

if desired, have a reduced end portion extending into the spring 84, asshown.

The movable contact carrying washer is mounted for arrestedreciprocating action inwardly of the housing to permit the engagementand the release of the prongs 68 in the apertures in the inner ends ofthe movable contacts 69 so that the movable contacts are free toreciprocate in and out of engagement with the thermally reactivecontacts 51. In the illustrative structure shown, the inner wall of theshell 60 is recessed for the movable contact carrying washer 10 so thatthe peripheral edge of the washer is engaged by a shoulder I3 of theshell 50 at one extremity of its motion and by the inner face of the capBl at the opposite end of its motion.

When this plug is inserted in a plug receptacle, the contacts 69 makeengagement with the thermally responsive contacts 51 against thepressure of the spring 54. When a current overload is imposed on thisplug the spaced ends of the thermally responsive contacts 81 separatesufficiently to remove the prongs 68 from the apertures in the contacts69 and the spring 64 kicks the plug shell and its rigidly mounted partsaway from the split washer 10 to break the connection.

In all of the disclosed constructions the thermally reactive strip willalso function from externally applied heat, as where the connection isused to disconnect a circuit in the event of fire, the overheating of anadjacent part, or the like.

The invention adapts itself to various structural changes withoutmaterial change in function. Where a substantially conventional plug isdesired to avoid the presence of the plug screw 30, the spring 25 can belonger than shown to resemble the spring 58 with or without its sheathcap 59. The plug contacts Hi can be riveted or screwed into supportingwashers, if desired, as is the plug screw 30. The plug shell 50 can beof resilient rubber material and can be grooved internally to receiveparts supporting washers and the like, as is plug 2. The plug cap Bl canbe closed, if desired, between the movable contacts 69 because with thewasher 10 against the cap 6| there is no obstruction to prevent therotation of the cap 6| with respect to the shell 60. In the engagementbetween the thermally responsive strip and the slide contacts theengaging parts could be reversed or altered in design somewhat withoutmaterial change in function. Both spaced pairs of strips 45 and 49 maybecapable of moving away from each other instead of but one strip beingmovable, as is shown, if desired.

It is to be understood that the particular embodiments of the inventionthat are shown and described herein are cited for purposes ofillustration and explanation and that, with the development ofindustrial equipment having similar functions, various modifications,substitutions and changes in the parts, constructions and adaptationsmay be made without departing from the invention as defined in theappended claims,

such as the substitution of thermally reactive or said plug contact, asubstantially inclined end part of said housing contact for guiding saidplug contact into engagement with said housing contact, means on saidplug receptacle contact for retaining said plug contact, and springmeans opposing the retention of said plug contact by said plugreceptacle contact.

2. An electrical connection adapted for making interchangeableengagement with house wall sockets and attachment sockets and the like,comprising in combination, a plug having a shell, a thermally reactivecontact in said plug shell, an exposed contact having a portionreleasably engaging said thermally reactive contact and having anotherportion projecting from said plug shell, a spring yieldingly resistingthe engagement between said thermally reactive contact and said exposedcontact, a shoulder on said exposed contact, an exposed contact mountingmeans having portions disposed on opposite sides of said exposed contactshoulder and free for limited axial movement in said plug shell, andexposed contact movement arresting means normally preventing theseparation of said exposed contact from said shell.

3. An electrical connection adapted for making interchangeable unionwith house wall sockets and attachment sockets and the like, comprisingin combination, a plug having a shell, a thermally reactive contactmounted in said plug shell, an exposed contact having one portionreleasably engaging said thermally reactive contact and another portionprojecting from said shell and said exposed contact being capable ofreciprocating action axially of said shell, means substantiallyoperatively preventing the separation of said exposed contact from saidshell, a mounting supporting said exposed contact and limiting the axialmovement thereof by its engagement with said means for preventing theseparation of said exposed contact from said shell, and a resilientmeans yieldingly opposing the engagement between said thermally reactivecontact and said exposed contact.

4. An electrical connection for interchangeably engaging house wallsockets and attachment sockets and the like, comprising in combination,a plug shell, a thermally reactive contact mounted in said shell, anexposed contact partly disposed within said shell and having anotherpart extending therefrom and said exposed contact being movable axiallyof said shell, a movable exposed contact supporting means in said shell,releasable interengaging means between said thermally reactive contactand the part of said exposed contact in said shell, removable means forpreventing the separation of said exposed contact from said shell, andspring means yieldingly urging said thermally reactive contact and saidexposed contact apart.

5. An electrical connector adapted for making interchangeable electricalconnection with electrical outlets and attachment sockets and the like,comprising in combination, a plug receptacle housing apertured for theadmission of electrical connections, a blade contact that is operativelymounted in said plug receptacle housing, a thermally responsive contactin said housing, means for releasably retentively joining said bladecontact with said thermally responsive contact, and spring meansopposing the retention of said blade contact by said thermallyresponsive contact.

6. An electrical circuit interrupting means, comprising in combination,a plug shell, a plug cap removably mounted on said plug shell, a

parts supporting means rigidly disposed substantially within said plugshell, a spring disposed within said plug shelland having one endrigidly secured with respect thereto, a thermally reactive concealedcontact strip disposed within said plug shell and having a part rigidlysecured with respect to said plug shell. a movable contact having oneend disposed within said plug shell and having an opposite end extendingaway from said plug shell and outwardly thereof and said movable contactbeing capable of reciprocating in and out of engagement with saidthermally reactive contact, a prong carried by said thermally reactivecontact and capable of releasably retentively engaging a part oi. theend 01' said movable contact that is disposed within the plug shellagainst the action of said spring tending to move said movable contactout of engagement with said thermally reactive contact, and a movablecontact mounting carrying said movable contact and capable ofreciprocating movement substantially within said plug shell andprevented from separation from said plug shell by engagement with saidremovable plug cap.

'7. An electrical circuit interrupting means, comprising in combination,a plug shell, a plug cap removably mounted on said plug shell, a springwithin said plug shell and having one end secured immovable with respectto said plug shell, a thermally reactive concealed contact disposedwithin said plug shell and secured in rigid relation with respect tosaid plug shell and terminating in an unattached end, a movable contacthaving one end adapted for engaging and being releasably retained by theunattached end of said concealed contact against the force of saidspring and having an opposite end projecting to outside of said plugshell for engagement with a house wall electrical outlet and the like,and a movable contact mounting adapted for reciprocating movement withinsaid plug shell that is limited in one direction by engagement with apart of said plug shell and in the opposite direction by engagement withsaid plug cap.

8. An electrical circuit interrupting means, comprising in combination,a plug shell, a spring disposed within said plug shell and having oneend mounted in rigid relation therewith and its other end free for theapplication of pressure thereagainst, a thermally reactive concealedcontact disposed within said plug shell and having one part rigidlysecured with respect to said plug shell and another unattached partcapable of movement on suflicient temperature change in said concealedcontact, a movable contact having one end releasably engageable by saidunattached part of said concealed contact and another end extending tooutwardly of said plug shell for engaging an electrical outlet and thelike, a movable contact mounting carrying said movable contactintermediate the ends thereof and adapted for reciprocating movementwithin said plug shell, and means for limiting the movement of saidmovable contact mounting within said plug shell.

9. An electrical circuit interrupting means, comprising in combination,a plug shell, a thermally reactive concealed contactin said plug shelland having a part rigidly secured with respect thereto and terminatingin an unattached end, a movable contact engageable by said thermallyreactive concealed contact and partly disposed in said shell and partlyextending therefrom, a mounting carrying said movable contact; andsubstantially floating in said shell, a resilient means yieldinglyopposing the engagement'between said movable contact and said thermallyreactive concealed contact, and means for limiting the movement of saidmovable contact mounting within said plug shell.

10. An electrical circuit interrupting means adapted for makinginterchangeable slip flat blade contact with house wall electricaloutlets and attachment sockets and the like, comprising in combination,a shell, a cap removably mountable on said shell, a parts supportingmeans disposed within said shell in rigid relation therewith, athermally reactive contact securely mountedon said parts supportingmeans and having an unsecured end, a movable contact substantiallyfloating in said shell for axial movement therein and having a bladeportion extending to outwardly of said shell, a shoulder on said movablecontact spaced from said outwardly extending blade portion thereof, asplit washer having a part disposed on either side of said movablecontact shoulder to provide a mounting for said movable contact, ashoulder on said shell engageable by said split washer to arrest themovement thereof axially of said shell in one direction and said caparresting the movement of said washer axially of said shell in theopposite direction, a spring having an end mounted on said partssupporting means and an opposite end adapted for engagement by saidwasher to resist the engagement between said thermally reactive contactand said movable contact, and interengaging means between said thermallyreactive contact and said movable contact whereby said movable contactis maintained in engagement with said thermally reactive contact againstthe pressure of said spring.

ARTHUR KEEFE.

